CMOS微功率鋰離子電池保護積體電路之設計研究

Research on CMOS Micro Power Lithium-Ion Batteries Protection IC Design

趙堯主(Jao-Chu Chao)

指導教授 ： 鍾文耀

中原大學/工學院/電子工程研究所/碩士(2003年)

https://doi.org/10.6840/cycu200300170

摘要

CMOS微功率鋰離子電池保護積體電路之設計研究
中文摘要
鋰離子電池由於使用上有安全性的考量，應用時需搭配額外的保護電路，使得電池盒效能可充分的發揮並可延長其使用壽命。本論文研究目標在於使用CMOS技術完成一個適用於可攜式電子產品之鋰離子二次電池保護晶片，其電路特性可達到在電壓與溫度變化時仍擁有精確臨界電壓判斷特性，內建有適當的遲滯機制以確保系統可靠度，並可微功率操作之電源管理系統。

電池保護系統偵測電池包電壓與充放電電流大小，將偵測結果經由狀態機器判斷後，再搭配適當的遲滯機制後輸出以控制外部開關，達到控制負載迴路或充電迴路之開關。其工作方式是使用偵測與拴鎖之概念完成，並以弱反轉區電路操作實現微功率系統。關鍵的電路方塊由寬擺幅固定轉導偏壓電路、時脈產生電路、除頻器、能帶隙參考電壓電路、交換式電容分壓電路、遲滯比較器、逆偏保護電路，及充電泵等所組成。

為了提高系統精確性，執行分壓動作使用電容式分壓機制，以減少溫度與製程上的影響。系統中置入剪波穩定運算放大器以消除放大器直流偏移電壓對能帶隙參考電壓電路輸出偏移的影響。在系統可靠度的考量上，強調電路低電壓工作(1.5V)與高共模拒斥比(比較器之PSRR>110dB)特性，使用遲滯電路防止寄生元件效應造成系統癱瘓，逆偏保護電路的使用可避免反相或負電壓造成晶片內部pn接面順偏。在節省系統功率上設計關閉電源機制，並搭配分時取樣技巧與弱反轉區電路操作可以有效達成微功率系統目的。

關鍵字：微功率、鋰電池保護、電晶體弱反轉區操作

關鍵字

鋰電池保護 ； 電晶體弱反轉區操作 ； 微功率

並列摘要

Research on CMOS Micro Power Lithium-Ion Batteries Protection IC Design

Abstract
The aim of this research is to design a Lithium-ion batteries protection IC for portable device applications. The major concerns on design techniques for power and temperature independent circuits, micro power biasing skill and reliability enhancements for system performance have been implemented and investigated by using a double-poly double metal CMOS technology.

The protection system detects battery cell voltage and charge/discharge current. According to detected results, the state-machine has been initialized to drive the system to switch external MOSFET and charge/discharge current loop. The sample and latch concept has been used to implement voltage monitoring, and analog circuits based on weak inversion operation are also involved to realize micro power application. Main circuit blocks built in this research are wide-swing constant transconductance bias circuit, clock generator, divider, bandgap reference, switch capacitor voltage divider, hysteresis comparator, reverse bias protection circuit, and charge pump.

For the accuracy issue, the capacitor voltage divider is used to reduce the effects caused by temperature and process variation. The chopper-stabilized technique is adopted to eliminate the offset voltage of OP amplifier. For the reliability concern, all circuits are designed with the emphases of low operating voltage (1.5V) and high PSRR (>110dB) characteristics. Hysteresis circuits are used to avoid unexpected system shutdown, which might be caused by some parasitic effects. The reverse bias protection circuit is used to prevent unnecessary pn junction forward bias. A 3.6V micro power system with 6.57 uA operating current is built in this research。

Key word: Micro power, Lithium-Ion Batteries Protection, Weak Inversion.

並列關鍵字

Lithium-Ion Batteries Protection ； Weak Inversion ； Micro power

參考文獻

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